I finally tackled this project. While my deck was being recored a couple of years ago, I had a hole drilled under one leg of the bow pulpit so I could run wires to a pulpit-mounted bow light. For various reasons it's taken a while to get to the next step in the project.
To make the wire exit hole in the tubing, I used three cobalt bits sequentially: 1.2mm, 3.1mm, and 9.9mm to drill into the pulpit tubing. My 5.4amp keyless chuck drill couldn't move the 9.9 bit smoothly without binding. A 9A drill with keyed chuck was able to hold the bit and finish cleaning up the hole.
The base was formed from two pieces of scrap star board shaped on a bandsaw. The edges could be smoother. The lower piece is U-bolted to the pulpit.
The light mounts to the upper piece of star board. The two pieces are held together by a pair of #10 screws. The larger hole is for the wires to pass through.
Relief holes for the mounting nuts are cut into the upper piece. The middle area between the U-bolt washers was filled with butyl tape before screwing the pieces together.
Once it's all together, it doesn't look terrible and should keep moisture away from the conductors and the LED bulbs.
I used white sugru to provide strain relief, chafe relief, and waterproofing where the wire exits the star board and where it enters the stainless tubing.
The step-down butt connectors tying the light's 18ga wires into the boat's 14ga bow light circuit are encased in shrink wrap and pushed back into the pulpit itself.
The light is an Attwood 2NM LED bow light.
Some day I'll remove the old light fittings from the hull.